1. Field of the Invention
The present invention relates to a wafer level packaging image sensor module and a method of manufacturing the same, and more particularly to a wafer level packaging image sensor module having a lens actuator which is composed of electroactive polymer and thus enables autofocusing and a method of manufacturing the same.
2. Description of the Related Art
Recently, as most pieces of portable mobile communication terminal equipment are provided with high-performance cameras of megapixel resolution, sales of mobile phones equipped with cameras has rapidly increased, and consumer's demands for moving images as well as still images of high image quality and high resolution has increasingly become keener.
In order to fulfill these demands, multifunctional mobile phones, which can execute autofocusing, closeup and optical zoom functions as well as the inherent shooting of a camera incorporated in the mobile phone, are being developed. In addition, modules of the cameras are becoming increasingly miniaturized. However, it is hard to satisfy various consumer's demands by developing mobile phone products incorporating therein autofocusing devices fabricated in a conventional manner of driving lenses.
Furthermore, since the conventional autofocusing device is constructed of a DC motor and a plurality of final reduction gears, its volume increases and drive noise of the motor is generated. In addition to these problems, since it is difficult to fulfill controlling of position due to extended starting time and stopping time during activation of the DC motor, transferring efficiency of a lens assembly is drastically decreased.
Meanwhile, because of the necessity of an increased number of pixels of camera modules and because of the necessity of miniaturization and high density packaging of camera modules required for the application to mobile phones, a wafer level camera module (WLCM) is being proposed. The wafer level camera module refers to a camera module, which is manufactured by producing an image sensor and a lens using a wafer level technology, so that it can be suitable for mass production and can be directly mounted on a main substrate of a mobile phone.
In the manufacture of the wafer level camera module, a wafer to wafer process is configured in a way such that a lens wafer is bonded in a bonding manner to a wafer equipped with an image sensor and is then subjected to a singulation process, thus manufacturing a camera module.
FIG. 1 shows a wafer level image sensor module which is manufactured using the above-described process. As shown in FIG. 1, after a lens wafer 7 is once bonded to a wafer 1 equipped with an image sensor 3 and electrode pads 5, control of focusing length is restricted because there is a measure of controlling a distance therebetween. Although an additional spacer is disposed between the lens wafer 7 and the wafer 1 including the image sensor mounted thereon for control of focusing length of the lens, there is considerable difficulty in precisely adjusting focusing length of a nonadjustable image sensor module.